Um...what!???

Question: When you see someone like this...with headphones jammed in their ears, an MP3 player attached to them...wouldn't you naturally assume that they are listening to music and CAN'T HEAR YOU??
Answer: YES

If the answer is indeed YES...and most people would agree the answer is YES...then why is it that people still insist on having full blown out conversations, or at least try to engage you in conversation whilst you have earbuds shoved in your ears? Sometimes I want to yell at them and say "pardon me, i'm not entirely sure if you have cataracts or some type of deformity in your cornea that's preventing you from seeing the miniature devices located inside my eardrums...but those are not hearing aids...believe it or not I'm actually indulging in some easy listening...so whatever you're trying to communicate to me...I can't hear it, nor do I want to. Buh bye."
Seriously, I don't understand this. I don't wear earbuds for fashion...they're very OBVIOUS because they have visible WIRES hanging from my head! It's okay if someone just says something quick in passing to you...like..."where the hell is the bloody elevator!?" Even though you can't hear them that's what you assume they are saying from their expression and demeanor....also it helps to read lips. However when you're standing on a train or in an elevator and someone is speaking to you in full length sentences and paragraphs....how can they possibly assume you can HEAR THEM!? You see their lips moving, they're looking at you, you assume "hmm they must be talking to me or this wall", then they look at you for some kind of acknowledgment or feedback and you have to go through the massive trouble of pulling out your earbud (its preferable to do it in a highly dramatic exaggerated motion so they get the idea)... and say "um...WHAT???" They then repeat and you are FORCED into idle stupid chit chat with a complete stranger when you COULD BE rockin out to the soundtrack of RENT singing "La Vie Boehm!" but noooooo...just because people don't get the concept that when you have headphones on it usually means I DO NOT WANT TO TALK TO ANYONE! I AM LISTENING TO MUSIC! Get a hint!!!!